package com.ja.util;  
  
import java.io.UnsupportedEncodingException;  
  
/** 
 * 转换字符串的编码 
 */  
public class ChangeCharSet {  
    /** 7位ASCII字符，也叫作ISO646-US、Unicode字符集的基本拉丁块 */  
    public static final String US_ASCII = "US-ASCII";  
  
    /** ISO 拉丁字母表 No.1，也叫作 ISO-LATIN-1 */  
    public static final String ISO_8859_1 = "ISO-8859-1";  
  
    /** 8 位 UCS 转换格式 */  
    public static final String UTF_8 = "UTF-8";  
  
    /** 16 位 UCS 转换格式，Big Endian（最低地址存放高位字节）字节顺序 */  
    public static final String UTF_16BE = "UTF-16BE";  
  
    /** 16 位 UCS 转换格式，Little-endian（最高地址存放低位字节）字节顺序 */  
    public static final String UTF_16LE = "UTF-16LE";  
  
    /** 16 位 UCS 转换格式，字节顺序由可选的字节顺序标记来标识 */  
    public static final String UTF_16 = "UTF-16";  
  
    /** 中文超大字符集 */    
    public static final String GBK = "GBK";  
  
    /** 
     * 将字符编码转换成US-ASCII码 
     */  
    public String toASCII(String str) throws UnsupportedEncodingException {  
        return this.changeCharset(str, US_ASCII);  
    }  
  
    /** 
     * 将字符编码转换成ISO-8859-1码 
     */  
    public String toISO_8859_1(String str) throws UnsupportedEncodingException {  
        return this.changeCharset(str, ISO_8859_1);  
    }  
  
    /** 
     * 将字符编码转换成UTF-8码 
     */  
    public String toUTF_8(String str) throws UnsupportedEncodingException {  
        return this.changeCharset(str, UTF_8);  
    }  
  
    /** 
     * 将字符编码转换成UTF-16BE码 
     */  
    public String toUTF_16BE(String str) throws UnsupportedEncodingException {  
        return this.changeCharset(str, UTF_16BE);  
    }  
  
    /** 
     * 将字符编码转换成UTF-16LE码 
     */  
    public String toUTF_16LE(String str) throws UnsupportedEncodingException {  
        return this.changeCharset(str, UTF_16LE);  
    }  
  
    /** 
     * 将字符编码转换成UTF-16码 
     */  
    public String toUTF_16(String str) throws UnsupportedEncodingException {  
        return this.changeCharset(str, UTF_16);  
    }  
  
    /** 
     * 将字符编码转换成GBK码 
     */  
    public String toGBK(String str) throws UnsupportedEncodingException {  
        return this.changeCharset(str, GBK);  
    }  
  
    /** 
     * 字符串编码转换的实现方法 
     *  
     * @param str 
     *            待转换编码的字符串 
     * @param newCharset 
     *            目标编码 
     * @return 
     * @throws UnsupportedEncodingException 
     */  
    public String changeCharset(String str, String newCharset)  
            throws UnsupportedEncodingException {  
        if (str != null) {  
            // 用默认字符编码解码字符串。  
            byte[] bs = str.getBytes();  
            // 用新的字符编码生成字符串  
            return new String(bs, newCharset);  
        }  
        return null;  
    }  
  
    /** 
     * 字符串编码转换的实现方法 
     *  
     * @param str 
     *            待转换编码的字符串 
     * @param oldCharset 
     *            原编码 
     * @param newCharset 
     *            目标编码 
     * @return 
     * @throws UnsupportedEncodingException 
     */  
    public String changeCharset(String str, String oldCharset, String newCharset)  
            throws UnsupportedEncodingException {  
        if (str != null) {  
            // 用旧的字符编码解码字符串。解码可能会出现异常。  
            byte[] bs = str.getBytes(oldCharset);  
            // 用新的字符编码生成字符串  
            return new String(bs, newCharset);  
        }  
        return null;  
    }  
  
    public static void main(String[] args) throws UnsupportedEncodingException {  
        ChangeCharSet test = new ChangeCharSet();  
        String str = "This is a 中文的 String!";  
        System.out.println("str: " + str);  
        String gbk = test.toGBK(str);  
        System.out.println("转换成GBK码: " + gbk);  
        System.out.println();  
        String ascii = test.toASCII(str);  
        System.out.println("转换成US-ASCII码: " + ascii);  
        gbk = test.changeCharset(ascii, ChangeCharSet.US_ASCII,  
                ChangeCharSet.GBK);  
        System.out.println("再把ASCII码的字符串转换成GBK码: " + gbk);  
        System.out.println();  
        String iso88591 = test.toISO_8859_1(str);  
        System.out.println("转换成ISO-8859-1码: " + iso88591);  
        gbk = test.changeCharset(iso88591, ChangeCharSet.ISO_8859_1,  
                ChangeCharSet.GBK);  
        System.out.println("再把ISO-8859-1码的字符串转换成GBK码: " + gbk);  
        System.out.println();  
        String utf8 = test.toUTF_8(str);  
        System.out.println("转换成UTF-8码: " + utf8);  
        gbk = test.changeCharset(utf8, ChangeCharSet.UTF_8, ChangeCharSet.GBK);  
        System.out.println("再把UTF-8码的字符串转换成GBK码: " + gbk);  
        System.out.println();  
        String utf16be = test.toUTF_16BE(str);  
        System.out.println("转换成UTF-16BE码:" + utf16be);  
        gbk = test.changeCharset(utf16be, ChangeCharSet.UTF_16BE,  
                ChangeCharSet.GBK);  
        System.out.println("再把UTF-16BE码的字符串转换成GBK码: " + gbk);  
        System.out.println();  
        String utf16le = test.toUTF_16LE(str);  
        System.out.println("转换成UTF-16LE码:" + utf16le);  
        gbk = test.changeCharset(utf16le, ChangeCharSet.UTF_16LE,  
                ChangeCharSet.GBK);  
        System.out.println("再把UTF-16LE码的字符串转换成GBK码: " + gbk);  
        System.out.println();  
        String utf16 = test.toUTF_16(str);  
        System.out.println("转换成UTF-16码:" + utf16);  
        gbk = test.changeCharset(utf16, ChangeCharSet.UTF_16LE,  
                ChangeCharSet.GBK);  
        System.out.println("再把UTF-16码的字符串转换成GBK码: " + gbk);  
        String s = new String("中文".getBytes("UTF-8"), "UTF-8");  
        System.out.println(s);  
    }  
} 